The Flow Cytometry Unit provides extensive support for NCI clinical protocols by providing diagnostic testing for leukemia and lymphoma in patients either on NCI clinical protocols or undergoing testing to determine eligibility for said protocols. The Flow Cytometry Unit provides clinical flow cytometric evaluation of blood, bone marrow, fine needle aspirates, tissue biopsies and body fluids for hematolymphoid neoplasia in NCI and NIH patients. The majority of flow cytometric testing performed by the Flow Cytometry Unit involves detection of minimal residual disease (patients are status post therapy at outside institution prior to enrollment on NCI protocol) and measurement of specific tumor cell characteristics mandated as requisite for enrolment in clinical protocols. Significant effort in the unit is devoted to delivery of numerous unique protocol mandated assays that are not offered by commercial laboratories or other academic institutions. The Flow Cytometry Unit is also actively engaged in education of the NIH staff and medical community at large in the proper utility of flow cytometry in medical practice.